JasonLion said:In an outdoor pool, chlorine is very effective, so there is little improvement to be had from an ozone system. The ozone system adds complexity, there are more things that can break, but does little to improve the water. Ozone is much more valuable for spas, where the bather load is much higher and chlorine is less effective at the higher temperatures.
However up to 90% of the chlorine used in a typical swimming pool is not burned up killing germs… rather it is worn away doing the work of oxidation or the breakdown of stuff in the water such as debris, oils, pollen, dust, suntan lotion etc. If we can reduce this workload on the chlorine we can free it up to do more of it’s job of sanitizing and disinfecting. When the chlorine is being used more exclusively for these things we can keep it at a lower level and still have safe, healthy swimming pool water.
….Even healthier, more natural water with less chlorine. That’s great news!
Ozonators for pool water do not bother the skin or hair and the results of the oxidation process have no bad environmental or health affects. As of this point I would stress ozone is a supplement for chlorine…. not a replacement. Be careful of people or companies that might be overselling it. You still need to do all the regular maintenance… it’s just the chlorine is going to be able to fulfill a much more narrow job description now… and you might not even know it’s there any more!
JasonLion said:Ozone and UV both act only right where they are being applied. UV doesn't make it outside of the UV cell at all, and ozone is consumed in the first couple of feet of pipe after the ozone injection point. In neither case is there any residual left in the bulk pool water.
JasonLion said:It has to do with the number of person seconds of swimming per gallon of water.
chem geek said:As noted with many spa users on another forum, an ozonator reduces chlorine consumption roughly in half when a spa is heavily used, so at least one person every day. When a spa is lightly used, such as just once a week, an ozonator results in a higher chlorine consumption because the ozone consumes some chlorine oxidizing it into chlorate. So as Jason noted, an ozonator is only helpful when the bather load is high which for a residential spa means that it is used nearly every day. This analysis is for detatched spas -- as Jason noted, a spa that circulates water with the pool probably won't need the benefit of the ozonator even if you were to use the spa every day.